Studies On The Preparation Of Starch Modified Flocculant And Its Characteristics

Starch grafting Polyacrylamide (SPAM) has the characteristics of natural macromolecular and synthesis macromolecular. Supported by rigid framework and linked with flexible branched chain of polyacrylamide, SPAM forms voluminous reticulate macromolecular as flocculant. Ionized modified SPAM has better effect on treating different kinds of wastewater than nonionic SPAM.In this paper, SPAM was initiated by potassium permanganate and sulfuric acid. Different factors of affecting graft copolymerization such as sulfuric acid concentration, potassium permanganate concentration and acrylamide concentration, reaction temperature, solvent dosage, adding sequence were studied. The optimal conditions: KMnO₄: 0.45mmol/L, H₂SO₄: 0.8mmol/L, Temperature: 60℃, adding sequence: St→Am→sulfuric acid→potassium permanganate. SPAM is initiated by a smaller quantity of initiator and has considerable grafting ratio, grafting efficiency and higher molecular weight was explained.The structure and characteristic of SPAM was characterized by means of IR and TGA. The results show that SPAM is the graft copolymer of starch and acrylamide and has better thermal stability than polyacrylamide (PAM).Cation SPAM (CSPAM) and anion SPAM (ASPAM) were prepared by modifying SPAM. The flocculating characteristic of SPAM, CSPAM and ASPAM to kaolin, oily wastewater, municipal wastewater and activated sludge were tested.